Looks kinda close to this one - "Unknown ACE-2100": https://theretroweb.com/motherboards/s/unknown-ace-2100

The location of DMA controllers and the ROMs nearby, the chips around the CPU, etc - very similar design.
But it's not exactly the same. The location and the type of the clock battery is different.

for more memory, you will be limited pretty heavily.

You will need a 16bit ISA ram expansion card, and will hit the 286's maximum memory ceiling at 16mb. The 286 architecture cannot "properly" exit protected mode, which means anything above 1mb will put the CPU out of real mode. Programmers of the time made use of an undocumented "Feature" of the CPU's LOADALL instruction to transition the processor to 'unreal mode' from protected mode.

https://en.wikipedia.org/wiki/Unreal_mode

Some DOS programs get uppity if they are not in genuine, bonafide real mode.

That said, your options for RAM expansion will be things like the BocaRAM/AT Plus, Intel AboveBoard Plus, Emulex persyst, AST RAMPage 286, AST RAMPage Plus, or something similar.

You *could* drop a lo-tech 2mb EMS in there, but.... thats 8 bit, and EMS only. Would not get you the same kind of experience.

I'd go with that last AST RAMPage Plus, myself. Nice 30pin simm slots.

Thanks for the replies, yeah looks like that motherboard, shame there is no manual with jumpers.

Just dont understand why its running st 6hz?

Its (one of) the slowest versions of the 286, which ran at 6mhz.

https://en.wikipedia.org/wiki/Intel_80286

Oh, ok ! Lol.

How easy / simple is it to swap the chip? Is it just matter of getting lets say 16mhz one and simply swap it?

There's some voodoo to check for, concerning the ISA Bus's crystal oscillator, but usually thats all there is to it, yeah. Make sure its the same package type. 286 came in an abundance of variations.

Stupid question but which one is the cpu?

I cant see your chip in your pictures.

If it is genuinely like the one cited on retroweb, its either PLCC or CLCC. the retroweb image has a heat spreader installed over the CPU, so I cant really tell.

In addition to that variant, the 286 also came in QLC, and PGA variants.

You would need the correct one for your board. PLCC/CLCC and PGA would be the easiest to replace. QLC would require special tools to remove.

Looks like this is the cpu on my board?

https://i.postimg.cc/FNwKGhxk/IMG-2500.png

That's a QLC one, and will need special tools to remove from that socket. DO. NOT. TRY. TO. LEVER. IT. OUT.

So this cpu wouldnt work?

https://i.postimg.cc/8D0WQQHN/IMG-2501.jpg

It likely *WOULD*, but again, YOU NEED A SPECIAL TOOL to remove that CPU from that socket.

I cant find a QLC chip removal tool when googling. Only PLCC.

Got any links?

Nevermind, I am very tired.... I really should be asleep right now. (got called to work to 'fix the internet' at a 24hr facility, havent been back to bed)

The three variants are,

CLCC, which looks like this--

PLCC, which looks like this--

and

PGA, Which looks like this--

You want the PLCC remover, for the correct number of pins.

I saw the PLCC chip, and my brain malfunctioned in its sleep deprived state, and said "That looks like a QFP package." (which, ironically, IS another variant of 386 that exists, but that is NOT replaceable.)

I should probably go to bed now before I hurt something.

Omarkoman wrote on 2025-05-29, 05:09:

- is bios on this updateable ?

Yes, by replacing the BIOS chips. It looks the BIOS chips in your board are UV-erasable EPROMs, so if you happen to have a UV eraser and a suitable EPROM programming device, you are likely able to re-use the BIOS chips already in the board. There is no way to upgrade the BIOS in-system.

Omarkoman wrote on 2025-05-29, 05:09:

- bios does not offer vga mode, would an update fix it?

You don't need to fix anything. "EGA" actually means "any video card with its own Video BIOS", so this includes VGA. The setting is in SETUP because the CGA and MDA cards did not have their own video BIOS, but the video BIOS code for those cards is included in the mainboard BIOS. The mainboard BIOS uses this setting to know whether it should enable its internal video BIOS (the CGA one if you choose "COLOR 40" or "COLOR 80"; the MDA one if you choose "MONO"), or it should rely on a dedicated video BIOS on an installed advanced video card (they call it "EGA", because that one was the first widely available advanced video card, but the mainboard BIOS doesn't care about what type of card it is, as long as it provides an IBM-compatible video BIOS).

Omarkoman wrote on 2025-05-29, 09:32:

Looks like this is the cpu on my board?

https://i.postimg.cc/FNwKGhxk/IMG-2500.png

Definitely looks like it:
https://www.cpu-world.com/CPUs/80286/Siemens- … 0286-1-N-S.html

Interesting thing is that's a 10MHz part. So the CPU itself should be able to go faster. Even though there's no manual/jumper guide, there are very few jumpers and it looks like the board speed (in 'high' mode) is determined solely by the oscillator in the corner of the board (outside of your pics). That will probably be a 12MHz model, as 286 runs at 1/2 of oscillator speed. If you're confident (de)soldering, you should be able to get 10MHz on the CPU by replacing it with a 20MHz oscillator. The CPU should be able to handle that - but no guarantee other parts will be able to keep up. So I'd personally suggest mounting a 4p socket for oscillators and getting a range (16, 20 maybe 24MHz) to play around with options above 6MHz on the CPU. It can be difficult to find new oscillators, but 2nd hand they can be had dirt cheap. I picked up a 16.257MHz one last week for EUR 5.90 including international shipping.

One other thing though: I see you (or a previous owner) removed the barrel battery, but there's still a lot of signs of corrosion from leaked battery fluid. I'd recommend giving that a thorough clean (my preferred method: first use vinegar, then rinse well with water, demineralize if tap water where you live is very hard) as there can still be corrosive stuff there that will keep eating away at your board. That would also give you the opportunity to get a good pic of the full board.

Thank you so much, that all makes sense! I’m happy to give the oscilator replacement a crack. Will see what i can source.

Is this the oscilator in my board?

https://i.postimg.cc/CYSnfChB/IMG-2503.jpg

Is it 2 pins? Like this one?

https://i.postimg.cc/js6ds9J8/IMG-2504.jpg

Omarkoman wrote on 2025-05-29, 10:01:

Is this the oscilator in my board?

https://i.postimg.cc/CYSnfChB/IMG-2503.jpg

It's one oscillator crystal, but not the one we care about. The one we care about (or possibly even two of them) is in the very corner of the board below the drive slots. It's a four-pin integrated oscillator, as seen on the photo on The Retro Web. Whatever you do about getting to higher clock rates, you should not change the 14.318 MHz crystal. This one determines the reference clock for the timer chip (how fast the DOS clock runs, the pitch of PC speaker sounds), but it does not directly influence system speed.